Self-soldering heat-coil.



PATENTED JUNElB, 1905.

Elm 792,315

P. B. 000K. SELF SOLDERING HEAT COIL.

APPLICATION FILED APR.13.1905.

ezwM 0% M UNITED STATES Patented June 13, 1905.

FRANK B. COOK, OF CHICAGO, ILLINOIS.

SELF-SOLDERING HEAT-COIL.

SPECIFICATION forming part of Letters Patent No. 792,315, dated June 13, 1905.

Application filed April 13, 1905. Serial No. 255,444.

To all whom it may concern.-

Be it known that I, FRANK B. Come a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Self-Soldering Heat-Coils, of which the following is a specification, reference being had to the accompanying drawings, illustrating same.

My invention relates to thermal protectors used for protecting electrical circuits and apparatus from abnormally large electric currents, and especially to thermal protectors of the self-soldering type, my principal object being to provide an improved construction in such a devicewhich greatly simplifies the manufacture of same and produces a much more sensitive protector than other types heretofore made.

This invention is an improvement on my Patent No. 776,218, November 29, 1904, for a self-soldering heat-coil.

I provide a metal tube through which a metal pin is soldered by an easily-fusible solder. On the tube are secured insulating-washers between which the heat-producing winding is wound around the tube. A toothed metallic shell is placed over the insulating-washers and secured thereto, the circuit through the device being from the pin through the winding to the shell. An abnormal current in the winding heats the solder and softens it and allows the heat-coil as a Whole to turn upon the pin. In this construction I greatly reduce the metal parts in the device, and consequently reduce the heat-radiating surface and the heat-conducting paths leading from the heated tube and solder. This makes a very sensitive coil and permits of greatly reducing the resistance of the heat-producing winding to produce a heat-coil which will operate in the same length of time required to operate other coils with the same current. From the drawings it can be seen that the only metal which is heated is the thin metal tube and the pin soldered therethrough, the washers on the tube being of insulating material, and consequently very poor conductors of heat. Therefore the heat is confined to the soldered joint, where it is utilized to soften the solder,

tion by reference to the accompanying drawings, in which- Figure l is an end elevation of the heat-coil of the invention. Fig. 2 is a longitudinal cross-sectional view of the heat-coil, taken on line A B of Fig. 1. Fig. 3 is an end elevation of the heat-coil, showing the opposite end from Fig. 1, with portions shown in crosssection and taken on line D E of Fig. 2. Fig. 4.- is an end view of the heat-coil and its cooperating spring members, showing the heatcoil and springs in operative position; and Fig. 5 is a view of Fig. 4, taken from the left thereof.

Like characters refer to like parts in the several figures.

The metal tube a. carries the insulatingwashers n a, which are placed thereon and held in place by annular projections m m. The holes in washers a 22 through which the tube a is inserted are preferably square or cornered, so that when the projections m m are formed on the tube 0. against the washers 42 n the tube a swells out, as shown in Fig. 3, due to the process of forming the projectionsm m, and nearly fills the square holes, which provents the washers '21 or from turning on the tube a after the annular projections m m are formed. The pin 0 is soldered through the tube a by an easily-fusible solder 7: and is provided with a flattened shoulder portion 7) on one end thereof, which fits into a depression in an ear .2 of spring 2/), and thereby prevents the pin 0 from turning. The heat-producing winding g is wound upon the tube a between the insulating-washers w. n. The metal shell f is corrugated to form teeth (Z (Z thereon and is slipped over the washers a2. a, one end of shellf being preferably formed over, as shown in Fig. 3, and the other end being provided with points 1) 2), formed over, as shown in Fig. 1, to hold the shell f in place on the washers a n. The terminals of winding 9 are connected to the tube a and shell f, respectively. There is an air-space between winding 9 and shell j, which prevents the heat from the winding from being conducted to the shell to any considerable extent. Spring -w is provided with ears .2 .2, between which the heatcoil is firmly held. Spring '0 is provided with a spur s, which engages a tooth d of the heatcoil when the apparatus is in a set position and tends to turn the heat-coil as a whole and release itself therefrom. When an abnormally large current traverses the winding g for a short length of time, it heats the tube a and softens the solder k, which allows the spring Q;

to turn the heat-coil upon the pin 0 and releaseitself from the tooth (Z. The circuit through the heat-coil is now broken and the device cools. When the heat-susceptible material cools and hardens, it resolders the tube a to the pin 0, and the apparatus is then ready to be reset for another operation. The spur 8 may now be reengaged with a tooth d of the device, which engagement resets the apparatus. When spring '0 is reset, the portion 2, thereof prevents same from being sprung back too far. The portion a of spring is for a-testplug to bearagainst to bear spur 8 out of engagement with the tooth (Z of the heat-coil .for

I claim as new, and desire to secure by Letters- Patent, is

1. In a device of the character described, a metal tube, a pin secured within the tube by heat-susceptible material, insulating-washers suitably secured upon the tube, heat-producing means placed upon the tube between the washers, and a corrugated sheet-metal shell placed upon the washers and inclosing the heat-producing means.

2. In a device of the characterdescribed, a spool comprising a metallic tube and insulating-washers threaded thereon, a hole in each washer through which the tube is inserted and which is provided with corners in which the metal of the tube is forced to hold the washers from turning upon the tube, and shoulders formed upon the tube on each side of the washers to hold same in place.

3. In a device of the character described, a spool comprising a metallic tube and insulating-washers threaded thereon, a hole in each washer through which the tube is inserted and which is provided with corners in which the metal of the tube is forced to hold the washers from turning upon the tube, shoulders formed upon the tube on each side of the washers to hold same in place upon the tube, a heat-producing winding wound upon the said spool, a toothed shell placed upon the washers and inclosing the whole, and a pin extending through the said tube and secured thereinby heat-susceptible material.

4:. In a device of the character described, a spool com prising a spindle and insulating ends, a heat-producing means carried by the spool, a corrugated metal shell placed upon vthe spool and points of the said shell bent over an end of the spool to hold the shell in place.

5. In apparatus of the class specified, a rotary portion comprising a tube, insulatingwashers carried by the tube, a toothed shell carried by the washers, and heat-producing means within the shell; an axis upon which the tube is normally secured by heat-susceptible material, means for supporting the axis in a fixed position, and means for engaging a tooth of the device to operate same under abnormal current conditions.

6. In apparatus of the class specified,.a rotary detentcomprising a tube, heat-producing means and insulatingwashers carried by the tube, and a shell carried by the insulatingwashers; an axis secured within the tube by heat-susceptible material, means for supporting the axis, and means for engaging the rotary detent to operate same when the heatsusceptible material is softened.

Asinventor of the foregoing I hereunto subscribe my name, in the presence of two subscribing witnesses, this 10th day of April,

FRANK B. COOK. Witnesses:

FREDERICK R. PARKER, H. B. HALL. 

